Telephone system



y 1940- i R. PFANNSCHMIDT 2,207,519

TELEPHONE SYSTEM Filed July 8, 1937 3 Sheets-Sheet 2 INVENTOR. RUDOLF PFANNSCHMIDT ATTORNEY.

July 9, 1940-. R. PFANNSCHMIDT 2,207,519

TELEPHONE SYSTEM F iled July 8, 1937. s Sheets-Sheet s INVENT OR.

' RUDOLF PFANNSCHMIDT ATTORNEY.

Patented July 9, 1940 TELEPHONE SYSTEM Rudolf Pfannschmidt, Berlin, Germany, assignol.

to Siemens & Halske Aktiengesellschaft 01' 'Wernerwerk, Siemensstadt, near Berlin, Germany Application July 8, 1937, Serial No. 152,552

. In France July 22, 1936 30 Claims.

The present invention relates to a circuit arrangement for telephone systems with registers. It concerns the arrangement of a register in a telephone system having a plurality of exchanges and concerns the particular construction of the register, which is provided with various approaches, the mode of operation of the register being adapted to various requirements in accordance with the characterization of these approaches on the establishment of a call between the various exchanges. The register itself is provided with devices which enable an impulse train transmitted to the register to be used for transmitting separate signals which do not serve for setting switches. A complete suppression of the impulse train can take place instead of the transmission of a signal. A further characteristic of the invention consists in that the register transmits ready impulses before receiving individual impulse trains in accordance with the manner in which the approaches are characterized. Moreover, by characterizing particular approaches the assessing device can be set out of action. When the assessing device is used the mode of transmission of ready impulses can be different.

The use of registers equipped in accordance with the invention is particularly advantageous in systems in which the signalling of impulses over connection lines is efiected by alternating current. Further characteristics of the invention are set out in the drawings and description.

Fig. 1 shows diagrammatically in the form of a circuit layout the arrangement'of the register (Reg, 3) shown in detailin Figs. 2 and 2A.

This register is connected up on incoming calls in that, for example, in the case of calls over one of the lines Bi to B8, one of the secondary switches M46 is set on the connecting repeater Ue. According to the embodiment the secondary switch is set by the transmission of an A. C. seizing impulse. When the repeater Ue has been seized a free register is connected up over the switch ll. As may be seen from Fig. 1, the connecting repeaterUe possesses a plurality of approaches some of which i are reached by the switches l l-M and others by the switches l5 and it. In accordance with the seizure of the connecting repeater over one of these approaches switching operations take place in the register which influence the mode of operation of the tered, a revertive impulse being transmitted to the calling station before each impulse train sent to the register. If the register is seized over the switches H-M five impulse trains are sent in to the register, of which the third impulse train 6 is converted .for the purpose of transmitting special signals. This third impulse train consists of one or two impulses according to the embodiment. If only one impulse is sent in to the register it is suppressed. If, however, two im- 10. pulses are sent in to the register as the third impulse train these efiect a reversal of current over the leads of the connecting line whereby a particular meter is connected to the connecting line. By these means incoming calls in a particular direction aredealt with in a diiferent Way from calls coming in over the same line from another direction. Such special treatment may be necessary for various reasons for example in the case of calls from a distant exchange. In the case of such calls only a single ready impulse is transmitted before the commencement of the reception of impulses by the register.

Naturally instead of connecting a special meter 9. special lamp may be connected up in order, for example, to indicate to an operator when a call has been set up from a particular direction and that she must listen in to this call. It is not necessary for the digits 1 and 2 to be used for differentation. Naturally any digits could be used.

If the register is seized over the switch IS the register is set in readiness for five impulse trains of which the third is used for transmitting special signals. In this case the manner of transmitting '5 revertive impulses when the receiving switches of the register are in the ready condition is different from the case when the register is seized over the switches I |-l i in which case also five impulse trains are taken up by the register. in the present case revertive impulses are transmitted before the reception of the first, second, third and fifth impulse trains. The third impulse train is used in this case in the same way as in the case in which the register is taken into use over the switches l l-l4.

The transmission of impulses for setting the group selector EEG-W3 commences when the register is only partly set, and later the switch IIIGW and the switch LW' to which the desired sub- Thus 40 Calls in the direction A proceed over the levels" 3 and 4 of the group selector IGWI with the aid of the register Reg. I, while calls passing in the direction A over level 4 ,of' the group selector IIGWZ and level 5 of the group selector IIGWI are set up by the aid of the register Reg. 2. The establishment of an incoming call over the connecting line B l will first be described with reference to Fig. 2 and then the establishment of incoming calls over the lines B5 and BB.

If a call is to be set up over the line La. Lb the seizing impulse for initiating the call is transmitted by alternating current. This alternating current is transmitted to relay MR1 by the transformer UcI. A rectifier GL is arranged in parallel with relay MRI. Relay MRI operates its contacts Zmrl and 3mrl. Contact 2mrl opens a point in the circuit for relay MU. Contact 37ml energizes relay MR in the following circuit: earth, contact 31ml, MR, battery and earth. Relay MR'operates its contacts Amr to 91m. Contact 41211" applies battery to the rotary magnet MD over contacts 41m", l5mm, l8mz and IZmt so that the magnet is impulsively operated by the interrupter UnI. The magnet MD operates its wipers am, bm, cm, dm, and em. Moreover, each time the rotary magnet MD operates it actuates contact Imd. Contact 5mr is closed while contacts Bmr and 1m? are opened. Through the closing of contact Smr the circuit in which relay MRI energizes is maintained. Contact Bmr applies earth to windings I and II of relay MT. Contact Qmr short-circuits relay MX.

During the transmission of alternating current the switch MW is now stepped forward until its wiper cm rests on a free line. If wiper cm finds the line shown for example at contact Cd to be the first free line the following circuit is established: earth, contact 81111", windings I and II of relay MT, lead Lc, wiper cm, the connection between contacts cd and Cd, which is not shown, resistance Wi3, contact 23k which is closed in the normal condition of the system, contacts 45s and I802, resistance Wi l, winding II of relay C, battery and earth. In this circuit relays MT and C energize. Relay MU is connected to wiper dm by contact I Ilmt. At contact I Imt a locking circuit is established by the application of earth to winding II of relay MT. Winding I of relay MZ which is disposed in series with winding II of relay MT does not energize in the circuit just described. The switch MD is brought to rest through the opening of contact lZmt. Contacts ISmt and Mmt are switched over but this does not produce any switching operation. If the transmission of alternatin current to relay MRI has not yet terminated the alternating current cannot influence succeeding devices in spite of contacts l3mt and Mmt having been switched over because contacts Gmr and 11721" are still open. The speaking leads are only switched through when the transmission of alternating current from the calling station is terminated and relays MRI and MR have released. The alternating current repeater seized by the energizing of relay C (winding II) is position I 'I.

contact IZmt.

provided with a connecting switch DW having an associated rotary magnet WD. This magnet operates wipers aw, awl, cw, cwI, cw2, dw and ew. In addition the magnet WD possesses a contact wd which is only operated when the magnet WD is energized.

If when a call is initiated the switch MW does not find a free outgoing line it advances into In this position relay MT operates since it finds battery over contacts Smr and Ifimw, and resistance W2'2. Relay MT brings the switch to rest by way of contact I2mt. At the end of the transmission of alternating current relays MRI and MR release. When contact Bmr is open relay MX energizes. Relay MX operates its contacts [5mm to I'Imzc. Contact IEmr opens the circuit of magnet MD. Contact IGmx connects up earth in preparation. Contact IImr is opened. If now a seizing impulse is again transmitted over the line La, Lb relays MRI and MR energize again. Hereupon relay MX is held energized by the closing of contact Bmr over earth, contact IGmx, relay MX, resistance Wit, battery and earth while relay MT is short-circuited by the earth connected to contact Ifimx.

Relay MT consequently releases and closes When the alternating current passing over the leads La' and Lb is disconnected relays MR and MRI also release. When relay MX releases the rotary magnet MD receives the impulse occasioned by the closing of contact I5mx whereby the switch is advanced to position 0. From this position it can then be started up by the transmission of a fresh alternatin current impulse over the line La, Lb in the manner already described. Successive transmission of alternating current seizing impulses can proceed for a definite time and only after the expiry of this period is a busy signal transmitted to the calling station. The automatic transmission is brought to an end by an alternating current impulse sent back when a free register is prepared. If a very short alternating current impulse is transmitted on initiating a call as may occur when using automatic calling devices when these are connected up the switch is unable to test when relay MR is released in the event of the switch MW not having found a free line before the termination of this impulse. The switch then advances automatically to posi tion 0 being controlled over wiper em. From this position it is then started up in the normal way by the next seizing impulse. As has been previously mentioned relay K is energized in the normal condition of the alternating current repeater. The circuit for this relay passes from earth over wiper ew and winding I of relay K to the lead L02 and battery in the group selector reached over the leads La2, Lb2, and L02. Contact 2370 has prepared the test circuit. The other contacts of relay K have been opened or closed or switched over without provoking any special switching operations. The contacts 29c to 33c are operated by the energizing of relay C when the alternating current repeater was seized. Contact 290 connects up winding I to relay C "in preparation. Contact 32c prepares a testing circult for the connecting switch DW for connecting a free register. Over contact 'lflq contact 330 connects winding I of relay B to the ter minal Ad which is connected to the terminal ad. Relay B is energized on the closing of contact 330 by the earth connected to wiper dm. Relay MU does not energize since being in series with winding I of relay B it does not receive sufiicient current. Relay B operates contacts 34b to 38b. Contact 3% brings about the energizing of relay E over earth, battery, resistance Will, relay E, contacts 68g, 34b and 300 and earth. Contact 355 prepares a locking circuit for winding II of relay B which, however, only becomes effective after relay Q has operated. Contact tfib prepares a locking circuit for the register. Contact 31b opens a point in the circuit of the lamp AL. Contact 3% in the lead Ld is closed. Relay E locks up at contact 39c. Contact Me switches on winding I of relay C. Contact Me shortcircuits winding II of relay Cl. Contact (3e short-circuits winding I of relay K which releases. Contact Me connects up lead La.2 for the outgoing impulse transmission. The release of relay K remains without effect until winding II of relay S is energized. Relay S (winding II) is energized in the following circuit: earth, contacts 28k, Me, 52p, and 6911, wd, winding II of relay S, battery and earth. Relay S operates contacts 558 to 493. Contact 418 short-circuits the thermo-relay Th. Contact 488 prepares'ior the energizing of winding III of relay S. Contact 498 causes the earth connected up at 28k to be connected to the rotary magnet WD. This latter energizes and operates contact wd. Hereupon relay S (winding II) releases. Contact 49s disconnects the magnet WD. The contact wrl on releasing reenergizes winding II of relay S. This interaction continues, the wipers of switch WD being thereby advanced until a free register is found. If the register shown in the drawings is free the following test circuit is established: earth, contacts 320 and 99g, winding II and I of relay P, 190i, cw, Sc, Wi9, lll'ilf, lQSrc, winding II of relay RC, battery and earth. In this circuit relays P and RC energize. The seizure of the register over wiper cw indicates that the register is to deal with five impulse trains of which the third is used for sending out special signals. Moreover the connection of the register over wiper cw determines that the latter is only to transmit a single revertive impulse.

When relay P operates it actuates contacts 5 p to 54p and Illllp. Contact 50p by applying earth directly over contacts 320, 3610 and 50p to winding I of relay P guards the seized register. Contact Sip connects winding II of relay U to wiper aw. Contact 52p brings the switch DW to rest by breaking the stepping circuit of the rotary magnet WD. Contact 531) breaks the lead Lb?! and contact 5411 switches through the lead Ld. Contact lilll'p connects the lead Li serving as an impulse lead for the outgoing impulses to lead LaZ. In the register relay RC has been energized. Relay RC prepares the register for the reception of impulses and transmits a signal to the alternating current repeater over contact l35rc by applying earth to the lead Ld to indicate that the register is ready to receive impulses. The earth applied at contact l35rc energizes relay R in the alternating current repeater in the following circuit: earth, contacts l35rc. lMrv, 532.4, wiper 2014, approach Sd, wiper dw, contacts 55p, 3822, Isle, thermo-relay Th, contact 15h, relay R, resistance Wz'9, battery and earth. Relay R energizes and operates its contacts EST and 561". Contact 551* energizes relay R! which is a slow-acting relay. Contact 56?" connects relay Q to the earthed lead Ld. Relay Q energizes. When relay RI energizes contacts 511! to 58H are operated. Contacts 5'! and 581'! connect the alternating current source We to the speaking leads sothat the alternating current is transmitted over the repeater Uel tothe line La, Lb. Contact 59?! connects relay T to the earthed lead Ld by way of contact IBIe. Relay T energizes and operates contacts 6015 to Biit. Contact Ellt short-circuits resistance Wi l. This, however, does not produce any switching operation. Contact 6It holds relay T energized independently of contact 5911. Contacts 621i and 631' open the speaking leads. The switching over of contacts 6H does not promote any switching operation. Contact 6515 short-circuits relay R. Relay R releases and thereupon relay Ri makes a delayed release. Relay Q does not release since contact B'lq has been closed and a locking circuit has been established to the earth connected over contact 3Ic. Winding II of relay B is also held by this earth when winding I of relay B deenergizes through the opening ofcontact 'Hlq. On the release of relay RI the transmission of alternating current to the calling station is terminated. Contact 6911 breaks the circuit for winding II of relay S. Contact 99: closes in preparation the circuit for the alarm lamp AL.

The transmission of alternating current from the source We, indicates to the calling station that impulses may be transmitted to the register. This transmission of alternating current when a plurality of calling impulses are transmitted can bring about the termination of the transmission of the calling signal as previously de scribed. The manner in which this alternating current is transmitted to the calling station and the equipment at the calling station does not concern the present invention.

After the application of the ready signal by the register to the lead Ld the thermo-relay Th heats up and thus supervises the orderly procedure of the call.

When impulses are transmitted by the calling station after the ready signal transmitted from the source of alternating current We has been received the A. C. receiving relay J is impulsively operated. Each time relay J energizes contact H7 is operated so that relay H follows the impulses.

Relay H controls contacts 12h. Contact 12h is closed wthout controlling any special circuits. Contact 13h connects the earth at contact 300 to relay T (I) over contacts 341) and 68g throughout the impulse transmission so that this remains operated even in the event of the earth. at contact i351'c being disconnected during the impulsing. Contact 14h short-circuits relay E intermittently without, however, causingfit to release. Contact 75h intermittently breaks the heating circuit for relay Th. Contact 16h repeats the incoming impulses to the register. This impulse circuit is completed from earth at wiper ew over contacts 76h and Elp, wiper aw, approach Set and contact 811m to relay A, battery and earth in the register.

If the calling station should delay dialling after receiving the ready signal which was transmitted by the application of earth to the lead Ld at contact l351c or after having commenced to dial should delay the transmission of further impulse trains relay Th becomes operative. Relay Th by switching over its contacts Tith energizes winding III of relay S in the following circuit: earth, battery, HIS, contact 11th, lead Lcl, contact 38b, contact 56p, wiper dw Sd, 2:54, 52. 5, 44m, l351'c, and earth. Relay S operates its contacts and locks up at 48s over contacts 66g and 21k and the lead Ld. Contact and l55rq break circuits in the chain of control 41s short-circuits relay Th; When relay Th releases the following short-circuit is produced for winding II of relay B: earth on the lead" Ld, contacts 27k, 66g, 48s, 71th (raised) contact 26k, winding II of relay B, contacts 351), 61g, 3lc and earth. Relay B in this circuit releases. The seized register is released by the opening of contacts 36b and 38b. The closing of contact 3712 switches on a lamp AL which indicates to the exchange staff that the calling station has not proceeded with the establishment of the call in the normal fashion. Relays T and S likewise release since the earth is disconnected at Ld.

If, however, the calling station should commence the further dialling after relay Th has energized but before relay B has released, relay B is prevented from being short-circuited on the release of relay Th in the case of particular calls in that when impulses are transmitted to the register contact i t lrv is open and the earth applied at contact 5351c cannot become operative to short-circuit relay B. This case only occurs when the register has been taken into use over the approaches Scl or S02 as will be described later.

On taking the register into use over the approach so relay RC was energized over winding II as previously described. Relay RC operates contacts I03 TC, lfi lrc, l21rc, l3lrc, 5357c, and Il2rc. Contact liln'c switched on winding I of relay RC in the testing circuit. Contacts were and [Tire are switched over without promoting any particular switching operation. Contact l3lrc short circuits winding I of relay Y. Contact lrc earths the approach Sd. Contact llErc applies earth to winding I of relay RR. Relay RR energizes and operates contacts 88m, lBSrr, l32rr, H3317", and H5317". Contact 8811" breaks the circuit of the impulses to be transmitted tom the register. Contact H3311 is opened. Contact 5321'?" removes the short circuit about winding I of relay Y. Contact I33Tr is temporarily closed. Contact i831? energizes relay RQ. Relay RQ operates contacts lililrq, l24rq, l5lrq, I53rq, 555m, and i69rq. Contact IfiSrq establishes a locking circuit which is independent of the operation of contact 38W. Contact l2 lrq' temporarily connects earth to the control circuit of the rotary magnets Di and D4 of the register switches of the register. Contacts l5lrq, l53rq switch wipers Ball to Sd l of the register switches. Contact lllOrq temporarily connects earth to the circuit over which the outgoing impulses are transmitted from the register.

Vfhen now impulses are passed into the register, i. e., when relay A is impulsively operated contacts l23a, [250a, l36a, MM and lGla are switched over by relay A. Contact l23d sets up the following circuit for the rotary magnet Dl of the first register switch DI; earth, battery, rotary magnet Dl, contacts [691, H532, l2l.3, i22.:l, 123a, l2 irq and earth. Magnet D! is operated and advances the wipers ldl, 2d! and 3dl one step. The rotary magnet Dl on energizing operates contact idl. The opening of contact l25a does not promote any switching operation. Contacts 136a and MSa are opened. These also do not promote any switching operation. Contact liila is closed and energizes relay RV. Relay RV is a slow-to-release relay and remains operated throughout the incoming impulse trains. Relay RV operates contacts 8612), 126M, [31m]. Marc and 391m. The opening of contact M lrv does" not cause any switching because the earth applied to contact l35rc remains connected up over the closed contact 145ml.

When the first impulse is terminated relay A releases. Its contacts are accordingly restored to normal. The rotary magnet DI is deenergized by the opening of contact l23a. The operation of the other contacts of relay A do not result in any switching. The wipers of the switch D! now rest in position I. No special switching operations take place in this position. When relay A receives the next impulse of the first impulse train it energizes again so that the magnet DI is energized again over contact 123a. This switches the wipers of the switch DI into position 2. The next impulse advances the switch to position 3. If this is the last impulse of the first impulse train relay A is deenergized for a prolonged period so that relay RV releases. Accordingly relay I, winding 2), is energized over the earth, contacts l35rc, I36a, l3'lrv, l38.l, wiper Zdl in position 3, relay I, battery and earth. Relay I operates its contacts IBM, 191, i381, l39.l, IBM. Contact I381 breaks the energizing circuit for winding 12' of relay I. It does not release, however, because contact 39.! sets up a locking circuit. Contact lfl9.l is switched over and connects the rotary magnet of the switch D2 to the control lead for incoming impulses. Contact 31.! temporarily connects the rotary magnet Di to the control circuit for outgoing impulses. Contact IBM is opened. When the second impulse train is transmitted to the register relay A responds to these impulses. When relay A energizes for the first time relay RV is energized again over contact 161a and remains energized during the second impulse train. The impulses are repeated to the magnet D2 over the contact [23a. The magnet D2 steps the wipers M2, M2, and 3112. A contact 4d2 associated with the magnet is opened only when the magnet energizes. If four impulses are transmitted to the magnet D2 during the second impulse train the wipers are advanced to position 4. At the end of the impulse train relay A remains deenergizedfor a prolongedperiod. Consequently relay RV- deenergizes. Relay RV causes relay II to energize over winding b over contact l3'lrv in the following circuit: earth, contacts I35rc, l38a, IS'h-v, I402, wiper 2d2, contact 4 in the bank associated with this wiper, winding 1) of relay II, battery, earth. Relay II energizes and operates its contacts. At contact i402 winding b of relay II is disconnected from contact l3'hv. Relay 11 does not release, however, since contact MLZ sets up a locking circuit. Contact 18.2 connects magnet D2 to the outgoing control circuit in preparation. Contact 0.2 connects the control circuit for the outgoing impulsingto relay X. Contact i512 is opened. Contact I522 is closed and establishes the following circuit for winding '11 of relay Y: earth, contacts 152.2 and ddl, wiper 3d! in position 3, contact 158171, winding II of relay Y, battery and earth. Relay Y energizes and operates its contacts. The operation of relay Y initiates the transmission of the impulse train registered in the switch DI. The transmission can take place while incoming impulses are being received.

In order not to make the understanding of the switching operations unnecessarily diflicult those switching operations which occur when impulses are received will be described first.

The third impulse train sent by the calling station may comprise either one or two impulses. If only one impulse is transmitted as the third IIZrk, IltrcI, relay X, battery earth. Relay RV' is energized over contact "31a. Relay X operates its contacts H402, Il5zc, 6a: and Idfix. Contact il lzc removes a short-circuit about winding I of relay RM. Contact H53: prepares an energizing circuit for relay RM and contact H61: prepares a circuit for relay RK. The closing of contact I462: has no significance at present. Through the closing of contact I25a. at the end of the impulse train relay RK is energized and relay X is held energized in the following circuit: earth, contacts Iz lrq, I25a, contacts I26ro of the slow release relay RV which has not yet released, contact IIIrm contact IIfizc, winding I of relay RK, relay X, battery, earth. Relay RK operates contacts Eric and IBBTk. Contact II2rk is switched over but does not bring about any switching operations. Contact IIBrk holds relay RK energized over its winding II and I I2rc. When now relay RV releases because no further impulses are transmitted after the first impulse relay X releases because its circuit is broken at contact IZBrv. Relay K, however, remains energized. The control circuitover which the incoming impulses are transmitted to the register switches is accordingly switched through to the rotary magnet D3 of the register switch D3 at contacts 21% and H51.

When the calling station transmits the fourth impulse train, for example the digit 5, the switch D3 is advanced five steps. The magnet D3 is energized over: earth, I24rq, I23a, I22.4, I2I.3, IIBLP, iIZrIc, IIEsc, ll8rm, rotary magnet D3,-battery and earth. While the rotary magnet D3 is being energized relay RV energizes again. The switch D3 steps its wiper Id3, M3 and M3 into position 5. Relay III energizes in the same Way as did relays I and II at the end of the impulse train. If the digit 6 is dialled as the last impulse train the magnet D4 is energized over the following circuit: earth, contact I24r2, I23a, I22.4, Hit of the control relay III which has energized meanwhile over winding b, magnet D4, battery and earth. The magnet D4 steps its wipers Idd to 3% into position 6. On the first step itself over contact I561. Relay RQ is deener gized through the opening of contact IIUA. Contact Iiillrq which opens is shunted by contact IBM which closes.

As already mentioned the impulse trains registered in the register switches commence to be transmitted while the incoming impulses are still being received. After the switching of the register switch DZ relay Y was energized over winding II and initiated the operation of switch DI.

When relay energizes over winding II the contacts I051 I3 iy, 163g, and I'IIy are switched over. Contact IUBy does not promote any switching operation. Contact I341 connects the adjustable resistance Wil in parallel with winding II of relay RR so that the latter relay operates as a slow-to-release relay. This slow-to-release feature of the relay may be controlled by adjusting the resistance W2! 4. Contact 53y switches on relay RVI so that the latter operatesits contacts. Contact IIIy breaks the circuit for relay RR which releases. The release of relay RR by opening contact IOIirr causes the magnet DI to energize over: earth, iolr lllfirr, IIJ'IJ, rotary magnet DI, battery and earth. The magnet DI advances its wipers. Contact I32rr clamps the winding I of relay Y by connecting up resistance Will. Contact 83nc'auses an impulse to be transmitted over the lead Li. When the magnet DI energizes contact 40 opens. Relay Y (winding II) consequently releases. When relay Y closes contact I Hy and relay RR (winding I) energizes again. Relay RR opens contact 88m" and 3671:. The opening of contact 8377 terminates the first outgoing impulse. Through the opening of contact IIIIirr the DI is deenergized. Accordingly contact 40 is closed again so that relay Y (winding II) again energizes over winding Iin position 4. Relay Y again causes relay RR to release whereby an impulse is tranmitted to the rotary magnet and a further impulse? is sent out over the lead Li. The interaction between relay ,Y and relay RR continues until the wiper MI of the switch DI reaches position II. In this position the circuit for energizing relay Y over winding II so that relay Y remains deenergized for a prolonged period. Through the prolonged deenergizing of relay Y, relay RVI is caused to release. Relay RV2 thereupon deenergizes for its circuit is broken at contact IIiEvI and contact I6Ilrv2 isclosed on the deenergizing of relay RVZ. A circuit is set up for windings I and II of relay RH. This circuit runs over: earth, battery, windings II and I. of relay RH, contact IISilroZ, position 11 of the wiper 3dl, contact ddI, I522 and earth. Relay RH operates its contacts and sets up a locking circuit foritself over its winding II and contact 15cm. Contact ream removes the damping from winding I of relay Y. Contact I62rh opens'a point in the circuit over relay RVI. Contact 951% breaks the circuit over which the impulses are transmitted, to a succeeding device on the advancing of the switch DI from position 3 to position II. Contact Ifiiirh switches on winding II of 'relay Y and the closure of contact I34y causes RR to release. The magnet DI receives an impulse over contact Ifilirr which brings the wipers of this magnet into position I). Relay RVI does not energize since contact M3271, is opened. On therelease of relay RR an impulse is not transmitted over contact 837'? because contact cam is opened. -In position II of the switch DI the circuit for winding 12 of relay I is broken so that this relay also releases In consequence the magnet D2 is con nected to the stepping circuit at contact IU'LI. When wiper 30 is set in position 9 the circuit for relay Y (winding II) is broken. Relay RH makes a delayed release. Meanwhile relay Y is released so that relay RR (winding I) is'energized again over contact I'Ily. Eight impulses are transmitted. This is the complementary number of the number 3 (the number of impulses received) with respect to the number 11 (the number of contacts in the switch). After the transmission'of the first impulse train the transmission of the second impulse train is initiated by the energizing of relay Y, winding II. This energizing circuit is as follows: earth, I5Irq, 4dI, 3dl, I531'q and 4d2, wiper 3d2 in position 4, I 581k, winding II of relay Y, battery and earth. Relay Y energizes and by opening contact I'IIy deenergizes relay RR. Relay RR energizes the rotary magnet DZ over contacts I061'1', I0I.I and I082. The switch D2 steps its wipers to position 5 whereby relay Y deenergizes through the opening of contact 4d2. Relay RR is consequently reenergized. Contact IIISTT is opened. When this step is taken by the switch an impulse is transmitted over the lead La-2 through the closing of the contact 88m. The next step of the switch is initiated by the energizing of relay Y (winding II) when the contact 4d2 of the magnet D2 is closed. Relay Y allows relay RR to release again whereupon another impulse is transmitted over contact 88W, the magnet D2 being advanced at the same time. The stepping and transmission of impulses continues until the switch D2 reaches position I I. In this position relay Y remains deenergized for a prolonged period. Relay RR is energized and contact 38m is open. The relays RVI and RVZ which were energized during the impulsing now fall back. When contact I BEIroZ closes relay RH energizes. Relay RH opens contact 99m so that the release of relay RR when the switch D2 is advanced from position II to position Q does not result in an impulse being transmitted by contact 8817. When the contact IEBrh is switched over relay Y energizes again. Relay RR releases and the magnet D2 receives an impulse over contact IIIorr which advances the wipers to position 0. In this position winding b of relay II is deenergized. Accordingly, the lead controlled by contact IIISTT is connected to the magnet D3 over contact I082. Relay Y (winding II) energizes after the release of relay RH which takes place when wiper M2 is set in position I] over. the following circuit: earth, contact I5Irq, 4dI, 3dl, I53rq, 4(12, I55rq, 4d3, wiper M3 in position 5, contact I 5am, relay Y, battery and earth. Relay Y energizes relay RVI over contact I63y and this energizes relay RVZ over contact I65rol. Relay RR releases. The magnet D3 receives current over earth, contacts I Mrc, IDBrr, I0'I.I, I082, I I9.3, rotary magnet D3, battery and earth, Magnet D3 advances the wipers from position 5 to position 6. During this stepping an impulse is transmitted over the lead La2 over contact 8811'. Winding I of relay Y and winding II of relay RR are damped during this stepping so that the velocity of the stepping of the switches D! to D4 and consequently the length of the individual impulses transmitted is adjusted to the requirements of the system in which the register is to Work. When in response to the operation of relays Y and RR the switch D3 passes to position II in the manner already described apropos of the preceding switches, relay Y after having transmitted six impulses is deenergized for a prolonged period whereupon relays RVI and RV?! release. Relay RH energizes over contact IfiilrvZ whereupon the switch D3 is advanced to position (I by the energizing of winding II of relay Y after contact I58rh has been switched over. No impulse is transmitted at this step. The damping of winding I of relay Y is removed at contact I3Ilrh. At contact II of wiper M3 the circuit for relay RH is broken. Relay RH releases and sets up the followin energizing'circuit for relay Y over the back contact I 58m: earth, battery, winding II of relay Y, contact I58rh, wiper M4 in position 6, contacts4d4, 3d3, 4J3, I531'q, 3d2, 4d2, I55rq, 3dl, 4dI, and I5Irq and earth. Relay Y causes the switch D4 to be advanced with the aid of relay RR which releases, the stepping of the switch being'brought about by the following circuit: earth, contacts IMTc, IOBrr, III'LI, I082, II9.3, l2i3.4, magnet D4, battery and earth. Relay III is deenergized when wiper 2113 is set in position I). The stepping of switch D4 to position II and the transmission of impulses over contact 8811' takes place in the same way as in the case of the stepping of switches DI to D3. When after having transmitted five impulses the switch D4 reaches position II relay F energizes over winding I. Relays RVI and RVZ release because relay Y remains deenergized for a prolonged time.

Contact I02 opens and causes relay RC to release. The following circuit is set up for winding I of relay Y: earth, contact I23 IZQT'Ul, 30m, winding I of relay Y, resistance Wil2, battery and earth. Relay Y energizes and operates the rotary magnet D4 over earth, contacts I d4 overwinding 0, until the switch D4 reaches the position 8. When contact I02) opens not only is relay RC deenergized, but also relay P, whereupon the irnpulsing lead L2 is disconnected through the restorationof contact IBUp to nor mal. Relay RR does not release during the stepping of the switch D4 from position II to position 0, since a locking circuit has been set up for its winding II over contacts I28 (relay F is energized in position II of the switch) and I 3377'. gized contact 3877' is kept open so that no im pulse is transmitted over the lead Li even if contact lIlflprernains open for a long time. The release of relay P in the switch DW brings about the release of the register so that after relays F and RR have released the register may again be seized for the establishment of further calls.

The station which has been selected is now called in any known manner. When the called party replies battery is applied to lead LbZ in the succeeding devices which arenot shown. This connection of battery causes relay Z to energize over its winding II in the following circuit: earth, contact 8Iz, winding II of relay Z, choke-coil Dr2, contact 5371, lead Lb2, battery and earth in the device which is not shown. Relay Z energizes and locks up over earth, battery, resistance Wi5, contact 84a, winding I of relay Z, contacts 6Iq and 3Io and earth. Contact 8Iz opensso that the earth connected to the chokecoil D1'2 over winding II of relay Z is disconnected. Relay R is energized in the following circuit: earth, contacts 300, 34b, and 2470, contact IBIz, relay Th, contact h, relay R, resistance WiS, battery and earth. Relay R operates its contacts and at contact 551' connects up relay, RI. Relay RI closes contact 5911 thereby energizing relay T (I) in the following circuit: earth, contacts 300, 34b, 24k, I8Iz, 5974, relay T, battery and earth. Through the energizing of relay RI On account of relay RR being held ener- Eli n e (A) alternating current from the source We was connected to contacts 51M and 5814, this resulting in the transmission of alternating current over the line La/Lh for signalling the fact that the called station has replied. When relay T energizes contact 6513 short-circuits relay R. Relay R releases and by opening contact 551 brings down relay RI. Relay Ri restores its contacts to normal, thereby terminating the transmission of alternating current over the line La/Lb. When relay R releases relay K energizes over winding II before relay T has released. The circuit passes from earth to battery, resistance W25, contact 84.2, winding II of relay K, the closed contact 6 32?, back contact 5dr, contact Blq and contact Me to earth. Relay K locks up at contact 2570. The current over the approach'Cd is amplified in that when relay K energizes the following circuit is established: earth, battery, winding II of relay C, contacts Gilt, 45s, and 23k, resistance W213, approach Cd, contact col, wiper cm, of the secondary switch MW, lead Lc, wind- II of relay MT, Winding I ofjrelay MZ, contact mi and earth. In this circuit relay MZ energizes over winding I and operates its contacts. At contact 2 lmz relay MZ locks upover winding II in the circuit: earth, contact I lmt, windings I and II of relay MZ, contact Zlmz, resistance Wi2, battery and earth. At contact 2lmz relay MZ connects the interrupter UNZ to the meter ZB. This circuit passes from earth, interrupter UNZ, contacts Hmw, Zlimz, and 2011211. to the meter ZB, battery and earth. By the operation of the interrupter the fee to be charged for this call is determined while the conversation is in progress. The current strength over L0 is reduced again on the release of relay T through the opening of contact 661.. When the called subscriber replaces his receiver in order to release the call or if he gives the clearing signal in any other way potential is applied to lead LL12. Accordingly relay S is energized over winding I.

- This circuit passes from earth over contacts 2% and 82a, winding I of relay S, choke-coil DH, contact limp, contact Me, lead L112 to battery in the devices which are. not shown. In this case also an alternating current impulse is transmitted over the line La/Lb and in response to this the seized devices in the calling exchange are released in any known manner. During the energizing of relay S the following circuit is established for relay R: earth, contacts 300, 34b, 368 and tale, thethermo-relay Th, contact h, relay R, resistance Will, battery and earth. Relay R causes relay Rl to energize whereupon alternating current from the soure We is transmitted over the line La/Lb over contacts 511"! and 581i. Relay T (I) is energized over contact 5911, whereupon relay R is short-circuited over contact Eat. Relays R and RI release. Relay T, however, holds up over contacts Git, i352, 46s, etc, 350 and earth. The alternating current impulse sent back-over the leads La. and Lb causes a prolonged release impulse to be transc mitted from the preceding devices to relay J.

magnet MD of the switch MW: earth, interrupter Uni, magnet MD, contacts iZmt, lflme, 15mm, the bank associated with wiper em, battery and earth. In this circuit the magnet MD receives impulses until wiper em has reached position ll. During the release of relay MZ contact Zllmz is also opened thereby terminating the influencing of the meter ZB. A test during further stepping of the wipers of switch MW into position ll does not take place because contacts Hmt and tmr are open. When relay C in the switch MW releases relays B, Q, Z and K are deenergized during the opening of contact 3Ic. During the closing of contact 69q when relay Q releases the following circuit is set up for winding II of relay S: earth wiper'ew, contacts 52p, 69g and wd, winding II of relay S, battery and earth. Contact Ms is closed whereupon the magnet WD is subjected to current. Magnet WD opens contact wd whereupon relay S (winding II) releases. This interaction between magnet WD and relay S continues until wiper ew has reached the rest position.

On the release of relay E contact Me was opened so that the battery potential promoting the release, connected to lead La2 in the succeeding devices does not find earth in the alterv nating current repeater (contact 2810). By this means the succeeding devices are restored to normal.

If the release is to be initiated by the calling station relay E is similarly short-circuited by the transmission of a special prolonged release impulse whereupon the release of the call takes place after relay E has deenergized. Contact Me opens the approach Cd. whereupon relays B, Q, Z and K are deenergized through the releasing of relay C and the opening of contact 310. The switch WD is restored to the rest position in the manner already described through the closing of contact 6911 while the switch MW restores to normal through the release of relays MT and MZ. Through the opening of contact 34s and the disconnection of the earth connected to contact 2870 from the lead hi2 the succeeding devices receive the signal intimating that the calling station has terminated the call.

If in case of the call just described in which the register was seized over the approach Sc the digit 2 had been transmitted to the register in place of the digit 1 the digit 2 is evaluated in a special way. The switching operations in the register are the same as those described in connection with the first call except that through dialling the digit 2 as the third impulse train earth is temporarily connected to the approach Sa. whereby relay U energizes over winding II and causes the metering switch ZA to be .con-

nected up when the connection is completed, instead of the metering switch ZB. The switching operations which occur in the register when two impulses constitute the third digit are as follows:

On the first impulse of the third impulse train after switches DI and D2 have been set relay X energizes in the following circuit: earth, contacts l2 irq, l23a, 221., 2133, Hi2, M2170 and liBrcl, relay X, battery and earth. Relay X energizes and operates contacts HM, H523, H50. and 5%. At the same time relay RV is energized over contacts mm. At the end of the first impulse relay RV does not release because the second impulse is received beforehand. For this reason contact 926m: remains closed. At the end of the first impulse the following circuit is set up for relay RK (winding I) and for relay X: earth,

contacts l24rq, l25a, IZB'rv, H'lrm and H63 winding I, relay RK, relay X, battery and earth. Relay RK operates its contacts and breaks the original energizing circuit of relay X at contact I lZrk. At contact lfifirlc relay RK locks up over its winding II. When relay A energizes for the second time relay RM also receives current over the following circuit: earth, contacts l24rq, l23a, 222.4, l2l.3, .Hfl.2, 2m, and 5.1:, winding I of relay RM, relay X, battery and earth. Relay RM operates its contacts. When the second impulse has ended winding II of relay RM is held energized in series with the magnet D3 (which does not energize) during the closing of contact 525a for a definite time. This circuit passes from earth at contact l24rq over contacts l25c, I 26m, and HBrm, winding II of relay RM, magnet D3, battery and earth. Relay X releases. During the opening of contact 61a after the second impulse has been transmitted relay RV releases. Relay RM remains energized for some time after the release of relay RV and the opening of contact l261v because its winding I is short-circuited at contact 41:. The following circuit is set up for winding II of relay U: earth, contact 35rm, back contact 86w, wiper aw, contacts 51p and 16h, winding II of relay U, battery and earth. Relay U energizes. Relay RM releases. The energizing of relay U over winding II causes relay MU in the switch MW to energize by closing contact 8011.. In addition a locking circuit is set up for winding I of relay U at contact 8011. This circuit passes from earth over contact Zmrl, relay MU, lllmt, dm, ad, Ad, 8%, IU, battery and earth. The energizing of wind ing II of relay U is brought to an end by the opening of contact rm. Relay MU connects up the metering switch ZA in preparation at contact 22mu and this metering switch is operated in place of the metering switch ZB when the i call is established and relay MZ operates.

The further establishment of the call proceeds in the same way as that described in connection with the first embodiment in that the impulse trains following the third impulse train are transmitted by relay A to the switches D3 and D4. The circuit for energizing magnet D3 passes over earth, contacts l241'q, l23a, 122.4, l2l.3, [10.2, I lZrk, H53: and ll8rm, magnet D3, battery and earth.

Naturally, instead of the evaluating device for the third impulse train comprising relays RM, RK and X a stepping switch or a similarly constructed relay switch could be used, the transmission of particular signals then being made dependent upon more and larger digits.

When the register is seized over another approach, for example over the approach Scl the evaluating device which in the present example comprises relays RM, RK, and X remains inoperative because only four impulse trains are received by the switches DI D2, D3, and D4. The fact that the register is to be taken into use over the approach Sci is determined in the secondary switch MW as has already been stated in connection with calls over the switch I5 in Fig. 1. In such cases the secondary switch MW is set on a free alternating current repeater, the wiper cm seizing one of the approaches Cdl For the sake of simplicity the manner of operation when setting up such a call will be described in the following only insofar as it differs from that occurring in the case of the first call to be set up.

When the switch MW is started by transmission of alternating current from the calling station in the manner already described the switch tests on a free approach Cdl by way of its wiper cm. In this approach a special relay Cl (winding II) is operated. In addition to this relay Cl relay C (winding II) also energizes in series with it. The switching operations in the switch MW are the same as described in connection with the first call. Relay Cl operates its contacts and at contact breaks the short-circuit over its winding I. The following locking circuit is established for winding I of relay Cl: earth, battery, resistance Wz'8, winding I of relay Cl, contact 18c! and earth at contact 3lc. Relay Cl is held energized over this circuit after its winding II has been short-circuited over contact Me. This short-circuit takes place on the energizing of relay E which occurs as already described when relay B energizes over its winding I. The short circuiting of winding II is efiected in order to be able to increase the strength of the current passing over wiper cm of the switch MW when the called party replies, with the maximum efilciency. At contact 19c! relay P is switched over on to wiper cwl of the switch DW. The starting of this switch and the testing on a free register takes place in the same way as was described in connection with the first embodiment except that at the approach Scl relay RCI energizes in series with relay RC. Relay RCI operates its contacts Ilircl, H3rcl, and l35rcl. Contact l45rcl breaks the lead to the approach Sd over which the ready impulses are transmitted to the succeeding device. By the opening of contact [45ml the earth connected to contact i35rc is made dependent upon contact Mdrv. Since relay RV which controls contact 244w is energized during each incoming impulse train and releases at the end of each impulse train a plurality of ready impulses can be transmitted from the register. Contact H3rc breaks the energizing circuit of relay X so that the third impulse train sent by the calling station passes to the rotary magnet D3 over the closed contact Hire and contact 5a: which remains closed.

When the register is seized relays RCI and RC energize as already described and relays RR (winding I) and RQ are energized through the closing of contact I'I2rc. A ready signal is transmitted over earth, contacts I 351'0, lldro and I 82.4, wiper 2114 in position 0, the approach Sd, wiper dw, contacts 54p, 38b, and l8lz, the thermo-relay Th, contacts 15h, relay R, resistance Wi9, battery and earth. Relay R on energizing operates relay RI whereupon the source We of alternating current transmits a ready impulse to the calling station. Relay T (I) is energized and short-circuits relay R in the manner previously described. Relay T remains temporarily energised over contacts Sit, Hz, 3817, 54p, wiper dw, approach Sd, wiper 2114, contacts 32.4, 144m and l35rc..

When the calling station transmits the first impulse train to the register relay A transmits these impulses to the switch DI. The setting circuit of this switch passes over earth, contacts I24rq, l23a, l22.4, 12!.3, 0.2, IUQJ, rotary magnet DI, battery and earth. Relay RV is energized at contact l61a and holds up throughout the impulsing. Contact l44rv is opened. Relay RT releases. At the end of the impulse train relay RB falls back whereupon winding 12 of relay I energized over earth, contacts I35rc, l36a, [31m and l38.l, and wiper Zdl. Relay I locks up over contact l39.l. When contact Mdrv is closed the following circuit is set up: earth, contacts I 35m, M irv, and 182. 5, wiper an, approach Sd, wiper dw, contacts 54p, 38b and I8Iz, relay Th, contacts 15h, relay R, resistance Wi9, battery and earth. Relay R energizes whereupon relay RI also energizes. Contacts 51M and 5811 connect up the source We of alternating current whereupon alternating current is transmitted over the line La/Lb. This signal causes the calling station to commence to transmit the second impulse train. On the energization of relay RI contact 59H is also closed so that relay T energizes. Relay T short-circuits relay R so that this relay and also relay RI release. 7 Relay Q has already been energized over contact 561, on the first ready impulse as was the case with the first embodiment. A locking circuit is set up over contacts S'Iq and 3Ic for relays Q and B (winding II).

When relay A receives the second impulse train contact lMrv is opened. In consequence the earth connected to lead Ld at contact I35rc is disconnected so that relay T is released. When the second impulse train has been received by the register and the switch D2 is set, relay RV releases again. Accordingly winding 17 of relay II is energized over M2, contacts IGILZ, I3'Irv, Itiia and I35rc. Relay II then holds up over contact I 4L2. Through the energizing of relay II the switch D3 is connected up over contact IIILZ since contact IIITcI is closed. Through the closing of contact IMrv after the second impulse train has been received relay R is energized again whereupon relays RI and T energize. An alternating current impulse is again transmitted to the calling station over contacts 5'IrI and SSH to indicate that the register is ready to receive the third impulse train. The energizing of relay T short-circuits relay R so that relay RI releases and terminates the transmission of alternating current from source We. After relay II has energized in the register the transmission of the impulse train registered in the switch DI commences in the manner already described through relay Y being energized over contact I522.

When the third impulse train is transmitted to the register relay T is deenergized through the opening of contact lt lr'u, whereupon relay R can again be energized for the purpose of transmitting a ready impulse when'the lead Ld is earthed again after the reception of the third impulse train on the release of contact Mdrv. This impulse indicates that the register is in a condition to receive the fourth impulse train. After the switch D3 has been set relay III is energized. When the fourth impulse train is transmitted to the register the wipers of this switch Dd are set in the position selected. When this setting is terminated relay RV falls back whereupon winding 1) of relay IV is energized over earth and contacts I 35m, M4111 and H5215, wiper 2M, contacts MM and MSW), relay IV locks up at contact IEIJA. At contact IZllA the magnet D4 is connected up for the purpose of advancing the switch when impulses are transmitted. Contact I GM is closed, thereby shunting contact Iilllrq. Relay RQ releases when contact I'IIIA opens. The further establishment of the call is the same as that described in connection with t the first embodiment.

It should be pointed out that if the setting up of the call is delayed relay Th becomes operative.

about by relay Th as was described in connection with the first embodiment by the energizing and subsequent release of this relay, the energizing of relay Th having already initiated the release without it being possible for the calling station to prevent the release by commencing to dial before relay Th has released.

The mode of operation of relay Th differs in the case of the present call in that if selecting impulses are received when relay Th is energized the release is prevented.

The manner in which this happens is that through the energizingof relay RCI when the register is seized over the approach Sci, contact 45ml is opened. If now after relay Th has energized delayed impulses are transmitted to the register relay RV is energized by relay A over contact I 61a. In consequence M411 is opened so that the earth is disconnected from lead Ld. The thermo relay Th then releases without a short-circuit having been set up for winding II of relay B.

The switching operations which occur when the metering impulse is transmitted on the reply of the called station takes place overthe ape proach CdI in the same way as described in connection with the establishment of a call over the approach Cd.

As may be seen from the preceding description the evaluating device comprising relays RM, X and RK is only then taken into use when the register is seized over wiper cm and the approach Sc,

only a single revertive impulse being transmitted evaluating device, with the exception that the ransmission of a revertive impulse, before the impulse train received after the evaluating device has operated, is suppressed.

If the register is to work in this way it must be seized over wiper 01122 by the wiper cw'Z being connected up in place of wiper cwI. This is made possible by the operation of contact I03 operated on the energizing of relay C3. In this case the alternating current repeater must be seized over the approach CcZZ. energizes in series with relay C3. Through the energizing of relay C2 in series with relays RC! and RC at wiper 0102 of the register the contacts of relay'CZ are also operated when the register is seized. Contacts I463: and I43rm are connected up preparatorily by contact I02. Contact 202 is closed and renders the opening of contact I I3r0l inoperative. Contact 302 is opened and rendersthe opening of contact IIIrcI inoperative. By rendering contacts IIIrcI II 3rcI inoperative in the case of the establishment of the present call the evaluating devices RM, RK, and X are set in operation in the same way as when in place of relays RCI, C2 and RC only relay RC energizes. Contact Ifl5rcI which is connected to wiper Md and thus to the control lead Ld is however operated once in such a way that a revertive impulse is transmitted to the calling station over contact lt irc only before the reception of the first, second, third, and fifth impulse trains.

Relay CI then and When relay RV has deenergized after the reception of the second impulse train relays R, RI and T are energized in the manner already described, thereby transmitting a revertive impulse to the calling station. Relay T remains energized over contacts 6H? and Isle and earth on the lead Ld.

On the commencement of the third impulse train contact Marv is opened. The earth connected to contact I35rc is, however, not disconnected from contact I824 since on the first impulse of the third impulse train relay X energizes and contact I461: is closed. The earth connected at contact I35'rc thus remains connected over contacts Mfirr, I02, I821! to the approach sd and thus to the lead Ld. The energizing circuit for relay X on the first impulse of the third impulse train passes from earth over contacts I24rq, I23a, I224, I2I.3, 0.2, 2%, 202, relay X, battery and earth. If only one impulse is transmitted as the third impulse train relay A .deenergizes at the end of this impulse but relay RV remains up for some time because it is slowto-release. The following circuit is established: earth, contacts I24rq, I25a, I26rv, IIIrm and 6:12, winding II of relay RK, relay X, battery and earth. In this circuit relay X remains energized for a moment and energizes relay RK over winding I. Relay RK locks up over winding II at contact lfifirlc. When relay RV releases the circuit just described is broken at contact I 26w. Relay X releases. Through the release of relay RV contact I4 1; is closed so that when contact I 4623 opened, earth was already connected to contact I35rc at contact I824. In this way the transmission of a revertive impulse when the evaluating device has operated is prevented.

When the fourth impulse train is transmitted by the calling station this passes to the rotary magnet D3 over earth and contacts I2 I1'q, I23a, I22.4, I002, IIZrlc, H51: and II8rm. Relay RV is energized again so that the earth on contact I35rc is disconnected from the lead Ld when contact M4112 opens. Relay T releases. When earth is again connected to the lead Ld on theclosing of contact I44rv after the switch D3 has been set, a revertive impulse is transmitted-in respect of the reception of the last impulse train which operates switch D4.

Similar switching operations take place when the third impulse train transmitted from the calling station comprises two impulses. In this case after the reception of the first impulse and after relays X and RK (winding I) have energized relay RV does not deenergize because the reception of the second impulse prevents this. A second impulse transmitted from the calling station then passes over earth and contacts lz l'rq; I23a, I224, I2I.3, H52, his, and Him, over relay RM and X to battery and earth.

Relay RM energizes. Relay X holds up. Relay RM switches on its winding II over contact IIBrm. Contact I43rm is closed and prevents the connection of earth to the approach sd being interrupted. When the second impulse is terminated relay RM receives current over its winding II for a prolonged period. This circuit passes from earth over contacts I24rq, I 25a, I26rv and 81m, relay RM (winding II), magnet D3, battery and earth. The magnet D3 has insufiicient current to energize. Relay X releases because its circuit is broken by the opening of contact I 23a. Relay RV releases. Only now does relay RM, whose winding I is short-circuited over contact I I 41c, commence to make a delayed release.

The delay period of relay RM is used to connect earth at contact 85rm over contact 86w, which has released meanwhile, to the approach Sc of the register so that through the energizing of relay U (winding II), relay MIT is connected up in the manner already described, thereby causing the meter switch ZA to be connected up. The actual metering and the completion of the release of the connection takes place in the manner already described in connection with the previous example.

What is claimed is;

1. In a telephone system, automatic switches. a register, means for seizing said register and for transmitting thereinto trains of impulses, means in said register for at times transmitting trains of impulses dependent upon all of the re ceived trains of impulses to thereby control said switches to extend a call and for at other times transmitting trains of impulses dependent upon only part of the received trains of impulses to thereby control said switches to extend a call. and means in said register effective only at said other times for determining the value of said last call from another part of the received trains of impulses.

2. A telephone system such as claimed in claim 1 wherein said first part of said received trains of impulses comprises one or more trains of impulses preceding and one or more trains of impulses succeeding said other part of said received trains of impulses.

3. In a telephone system, automatic switches, a register for receiving a predetermined number of call-directing trains of impulses and for transmitting to said switches a corresponding number of trains of impulses dependent upon said received call-directing trains of impulses to thereby control the extension of a call over said switches, means for at times seizing said register and for transmitting thereinto trains of impulses of which said predetermined number of call-directing trains of impulses are only a part, and means in said register for at said times determining from another part of said last trains of impulses the value of a call extended in accordance with said call-directing trains of impulses.

l. In a telephone system, automatic switches, a register, means for seizing said register and for transmitting thereinto a characterizing train of impulses preceded and succeeded by call-directing trains of impulses, means in said register for causing trains of impulses dependent only upon the call-directing trains of impulses to be transmitted from said register to control said switches to extend a call, and means in said register for determining the value of said call from said characterizing train of impulses to enable said register to transmit a characterizing signal in dependence upon the value of said call according to said determination.

5. In a telephone system, automatic switches, a register, means for seizing said register and for transmitting thereinto trains of impulses, means in said register for at times diverting part 01' the received trains of impulses, means in said register for causing trains of impulses dependent only upon the received trains of impulses which are not so diverted to be transmitted from said register to control the extension of a call over said switches, and means in said register for determining the value of said call from said diverted part of the received trains of impulses to enable said register to transmit a characterizing signal in dependence upon the value of said call according to said determination.

6. In a telephone systenna register, means for seizing said register and for transmitting thereinto trains of impulses, means in said register for at times diverting part of the received trains of impulses, means in said register for causing trains of impulses dependent only upon the received trains of impulses which are not so diverted to be transmitted fromsaid register to control the extension of a callover said switches, and means in said register for determining the value of said call from said diverted part of the received trains of impulses and for causing said register to transmit a characterizing signal only if said call, according to said determination, is of a predetermined value.

'7. In a telephone system, a register, means for at one time seizing said register and for transmitting thereinto call-directing trains of im pulses, means for at another time seizing said register and for transmitting thereinto calldirecting trains of impulses and an interposed call-characterizing train of impulses, impulse transmitting devices in said register, call-evaluating means in said register, and means in said register for, at said one time, bringing said transrnit ting devices successively under the influence of the trains of received impulses to record upon each device in turn the value of a received train and for, at said other time, bringing said transmitting devices successively under the influence of the received call-directin trains of impulses only and for diverting said interposed train upon receipt to said call evaluating means.

8. In a telephone system, a register, an impulse receiving circuit and an impulse transmitting circuit in said register, digit storing devices in said register, call evaluating means in said register, means for seizing said register and for transmitting thereinto trains of impulses, means for at times connecting said storing devices successively to said receiving circuit to receive said trains of impulses and at other times for connecting certain of said storing devices successively to said receiving circuit to receive part of said trains, then for connecting said cell evaluating means to said receiving circuit to receive a second of said trains, and then for connecting the remainder of said storing devices to said receiving circuit to receive a third part of said trains, and means for connecting said storing devices to said transmitting circuit in turn to transmit from said register trains of impulses dependent upon the trains of impulses received by said devices to thereby direct the extension of a call, said call evaluating means effective to function in a manner dependent upon. the evaluation of said call as determined from said second part of said received trains of impulses.

9. In a telephone system, automatic switches, control equipment having access to said switches, means for seizing said equipment over any of a plurality of approaches and for transmitting thereinto trains of impulses, means in said equipment for controlling th extension of a call over said switches in accordance with all or part of said trains of impulses, and means in said equip" ment effective at times in accordance with the approach over which said equipment was seized to determine the value of said call from a part or" said trains of impulses.

In a telephone system, automatic switches, control equipment having access to said switches, means in said equipmen for receiving trains of impulses and for extending a call over said switches in accordance with all or'part of said trains of impulses, means for seizing said equipment over any of a plurality of approaches, and means in said equipment efiective in accordance with the approach over which said equipment was seized for transmitting a signal when said equipment is prepared to receive a certain one of said trains of impulses or when said equipment is prepared to receive each of said trains of impulses or when said equipment is preparedto receive certain predetermined ones of said trains of impulses.

11. In a telephone system, automatic switches, a register, means for seizing said register over any of a plurality of approaches and for transmitting thereinto trains of impulses, and means in said register effective in accordance with the approach over which said register was seized for either transmitting trains of impulses dependent upon all of the received trains of impulses to thereby control the extension of a call or for 1 transmitting trains of impulses dependent upon only a part of the received trains of impulses to thereby control the extension of a call over said switches. 1

12. In a telephone system such as claimed in claim 11, means effective when trains of impulses clependent upon only a part of said received trains of impulses are transmitted from said register to control the extension of a call over said switches for determining from another part of the received trains of impulses the value of said call.

13. In a telephone system, automatic switches, a register, means for seizing said register over any of a plurality of approaches and for transmitting thereinto trains of impulses, said register effective to transmit trains of impulses depending upon all or part of the received trains of impulses to control the extension of a call over said switches, and means in said register effective at times in dependence upon the approach over which said register was seized for determining the value of said call from a part of the received trains of impulses.

14. In a telephone system, automatic switches, a register, means for seizing said register over any of a plurality of circuits and for transmitting thereinto trains of impulses, means in said register eifective only if said register is seized over a predetermined one of said circuits for diverting one of the received trains or impulses, means in said register for causing trains of impulses dependent only upon undiverted received trains of impulses to be transmitted from-said register to control the extension of a call over said switches, and means in said register for determining the value of said call from said diverted train of impulses.

15. A telephone system. such as claimed in claim i l, wherein said first means transmits into said register when said register is seized over said predetermined circuit an additional call characterizing train of impulses to be diverted for said determination.

16. In a telephone system, control equipment having a plurality of primary approaches, a register having a plurality of secondary approaches corresponding to said primary approaches, and means for seizing said control equipment over any one of said primary approaches and for transmitting thereinto trains of impulses, said control equipment eiiective responsive to said seizure to seize said register over the secondary approach corresponding to said primary approach, said register effective to receive said trains of impulses and to transmit trains of impulses corresponding to all or part of the received trains of impulses depending upon the secondary approach over which said register was seized.

1'7. In a telephone system, control equipment having a plurality of primary approaches, a register having a plurality of secondary approaches corresponding to said primary approaches, means for seizing said control equipment over one of said primary approaches and for transmitting thereinto trains of impulses, said control equipment eiiective responsive to said seizure to seize said register over the secondary approach corresponding to said primary approach, said register eiiective to receive trains of impulses and to transmit trains of impulses dependent upon all or part of the received trains of impulses, and means in said register effective at times in dependence upon the secondary approach over which said register was seized for making a determination from a part of the received trains of impulses upon which said transmitted trains of impulses are not dependent to enable a signal to be transmitted to said control equipment in accordance with said determination.

18. In a telephone system, lines of difierent classes, a plurality of registers, each of said registers having a plurality of approaches, automatic switches, means for seizing any one of said lines and for transmitting trains of impulses thereover, and means responsive to said seizure for seizing an idle one of said registers over an approach dependent upon the class of the calling line and for placing said register under control of said calling line to receive said trains of impulses, said register effective in dependence upon the approach over which it is seized to cause a signal to be reverted over said line responsive only to said seizure of said register or to cause a signal to be reverted over said calling line responsive to said seizure of said register and also responsive to the receipt of each of certain consecutive ones of said trains of impulses or to cause a signal to be reverted over said calling line responsive to said seizure of said register and also responsive to the receipt of each of certain nonconsecutive ones of said trains of impulses.

19. In a telephone system, automatic switches, control equipment having access to said switches, and means for seizing said equipment and for transmitting thereinto trains of alternating current impulses to extend a call, said equipment eifective to cause trains of direct current impulses dependent upon all or part of said trains of alternating current impulses to be transmitted from said equipment to control the extension of said call over said switches, said equipment also efieotive to cause an alternating current signal to be transmitted to the calling station when said equipment is prepared to receive certain of said trains of alternating current impulses.

20. In a telephone system, a register, a line, means for seizing said line and transmitting thereover trains of alternating current impulses to extend a call, means for receiving said trains of alternating current impulses and for transmitting identical trains of direct current impulses to said register, said register efiective in accordance with certain of said trains of direct current impulses to control the extension of said call over said switches, said register also efiective to originate a direct current signal when it is prepared to receive certain of said trains of direct current signals, and means responsive to said direct current signals for transmitting an alternating current signal over said line to said calling station.

21. In a telephone system, automatic switches, junction equipment having access to said switches, a register associated with said junction equipment, line equipment having access to said junction equipment, means in said line equipment for seizing said junction equipment and for transmitting thereinto trains of impulses to infiuence said register, means in said register for at times transmitting trains of impulses dependent upon only a part of the received trains of impulses to thereby control the extension of a call over said switches from said junction equipment, means in said register for determining the value of said call from another part of the received trains of impulses and for transmitting a signal to said junction equipment if said call is of a predetermined value, and means in said junction equipment for transmitting a signal to said line equipment responsive to the receipt of said first signal.

22. In a telephone system, automatic switches, a register, means for seizing said register to transmit thereinto trains of impulses, said register effective to receive trains of impulses and to control the extension of a call over said switches in dependence upon all or part of said received trains of impulses, means for releasing said register if the first of said trains of impulses is not received within a predetermined time after said seizure, and means in said register effective at times for determining the value of said call from a part of said received trains of impulses upon which said extension of said call does not depend.

23. In a switching system, line equipment individual to a specific line, control equipment accessible to said line equipment, means in said control equipment for receiving alternating current impulses, said line equipment efiective responsive to a seizing impulse of alternating current over said line to seize said control equipment, means in said line equipment for extending a connection from said line to said impulse receiving means in said control equipment responsive to said seizure, and means in said line equipment for preventing the completion of said line connection to said impulse receiving means until the cessation of said seizing impulse of alternating current.

24. In a telephone system, automatic switches, a register sender, means for seizing said register sender to extend a call and for transmitting thereto call-directing digits, means for diverting a part of the transmitted digits, said register sender eifective to control said switches in accordance only with the digits which are not so diverted thereby to extend said call, and means for determining the value of said call from said diverted part of the transmitted digits.

25. In a telephone system, automatic switches, a register sender, means for seizing said register sender to extend a call and for transmitting thereto call-directing digits, means for diverting a part of the transmitted digits, said register sender efiective to control said switches in accordance only with the digits which are not so diverted thereby to extend said call, and means for determining the value of said call from said diverted part of the transmitted digits and for transmitting a call-characterizing signal in dependence upon said determination.

26. In an automatic telephone system, means for transmitting a succession of call-directing digits, means for diverting a part of the transmitted digits, automatic switches controlled in accordance only with the digits which are not so diverted thereby to extend'a call, and means for determining the value of said call from said diverted part of the transmitted digits and for transmitting a call-characterizing signal in dedependence upon said determination.

27. In an automatic telephone system, means for transmitting a succession of call-directing digits, means for diverting a part of the transmitted digits, automatic switches controlled in accordance only with the digits which are not so diverted thereby to extend a call, and means for determining the value of said call from said diverted part of the transmitted digits and for transmitting or withholding a call-characterizing signal in dependence upon said determination.

28. In a telephone system, a register adapted to receive a plurality of digits, means for seizing said register over any of a plurality of paths, and means in said register effective in accordance with the path over which said register was seized for transmitting a signal either when said register is prepared to receive only a certain one of said digits or when said register is prepared to receive each of said digits.

29. In a telephone system, a register adapted to receive a plurality of digits, means for seizing said register over any of a plurality of paths, and means in said register efiective in accordance with the path over which said register was seized for transmitting a signal either when saidregister is prepared to receive only a certain one of said digits or, alternatively, when said register is prepared to receive each of a plurality of said digits.

30. In a telephone system, a register adapted to receive a plurality of digits, means for seizing said register over any of a plurality of paths, and means in said register effective in accordance with with the path over which said register was seized for transmitting a signal either when said register is prepared to receive each of said digits or, alternatively, when said register is prepared to receive only certain predetermined ones of said digits.

RUDOLF PFANNSCHMIDT. 

